Multiple local circuit for electric telegraphs



(No Mfldel.) 2 Sheets-Sheet 1.

P. L. POPE.

MULTIPLE 'LOGAL CIRCUIT FOR ELEGTRIO TELEGRAPHS. No. 329,412. Patented Oct. 27, 1885.

N PETERS. Ifiohrhlhagmphcn Washinglun. D. C.

(No Model.) 2 Sheets-Shet 2.

F.L.POPE.

MULTIPLE LOCAL CIRCUIT FOR ELECTRIC TELEGRAPHS. No. 329,412. PatentedOot. 27, 1885.

wvewtoz N. PETERS, Photo-Lithographer, Walhmglcn, D. C.

NITE STATES ATENT Erica FRANK L. POPE, OF ELIZABETH, NElV JERSEY.

SPECIFICATION forming part of Letters Patent No. 329,412, dated Cetober 27, 1885.

Application filed March 20, 1885. Serial No. 159,592. (No model.)

To all whom it may concern.-

Be it known that I, FRANK L. Porn, a citizen of the United States, residing in Elizabeth, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Multiple Local Circuits for Electric Telegraphy, of which the following is a specification.

In making use of the dynamo-electric machine for the purpose of supplying electric currents for large telegraph-stations the employment of such machines for the supply of the local circuits (which, as is well-known, consume by far the larger portion of the total electric energy required at any one station) has heretofore been attended with much prac tical difficulty. The volume or strength of electric current required in each local circuit is many times greater than that required in any of the main or long line circuits, and each individual local circuit is, moreover, required to be alternately made and broken without appreciably affecting any of the others. These requirements have hitherto made it necessary to group the local circuits in parallel or multiple arc with the generator. the local circuits, including the sounderthe instrument ordinarily usedis only about four ohms, and for this reason, when a very large number of these-for example, one hundred, or more-are placed in multiple arc with a single dynamo-machine, the combined or joint resistance of all the local circuits becomes considerably less than the minimum resistance which it is practicable to give to the dynamoelectric machine, and hence under these circumstances the greater portion of the total electrical energy developed is expended in the useless and injurious heating of the machine itself.

My invention consists in an improved organization of the circuits and apparatus by means of which each sounder or local instrument may be at all times supplied with its required proportion of the total electric energy, and may be independently actuated without appreciably affecting the operation of other instruments supplied from the same source, while at the same time in the system as a whole any required proportion between the resistance of the armature of the dynamoelectric machine and the total resistance of- The resistance of fered by the whole number of local instruments may be established and maintained.

In the ordinary operation of a telegraphic sounder, according to the conventional alphabetical code, the local circuit which actuates said sounder is alternately opened and closed at rapidly-recurring but irregular intervals.

It is for this reason that under the ordinary 6o arrangement it is impracticable to place two or more Sounders with their circuit-breaking relays in series in the same local circuit, as each circuit-breaker would in this case not only affect its own sounder, but all the others in the same series. In my invention this difficulty is obviated by constructing the armature of each relayin such a manner that while it opens and closes a branch circuit containing its own sounder in the usual manner, yet, while the circuit through said sounder is broken, it is closed through another branch containing an equivalent resistance, and thus the local circuit as a whole remains unbroken, while the strength of the current traversing it is at all times practically the same.

In the accompanying drawings, Figure 1 is a diagram illustrating one form of my invention; and Fig. 2 shows a modification of the same, which may be used with advantage when the number of instruments in the system is considerable. I

Referring to Fig. 1, E is a dynamoelectric machine or other suitable generator of electricity. M and M are the electro-magnets of 8 5 two independent relays which are included in different main circuits or telegraph-lines. As the connections of both these relays are alike, it will suffice to describe one of them only. The armature-lever m of the relay is provided 0 with a suitable retractor, t, and vibrates to and fro between limitingstops b and a. When no current is traversing the relay-magnet M, the armature-lever m is held against the rear contact-stop, c, by the tension of the retractor 5 t, and bears against the free end of a delicate contact spring or tongue, (I, mounted upon an insulating support, f, and separates said spring from the front contact-stop e. Awire or other conductor, 1, leads from one pole rco (for example, the positive pole) of the generator E to the contact-spring d. The wire 2 leads from the front stop 6 to the sounder S, and from thence to the point i. Another wire,

4 m ma n 3, leads from the armature-leverm to the artificial resistance or rheostat R, and thence to the point 4, where it joins the wire 2, and from thence the wire 5 proceeds to the contact spring or tongue d of the next relay of the series, the connections of which are arranged in precisely the same manner as the first, and are designated by corresponding letters of reference. From the last relay of the series a wire, 8, returns to the negative pole of the generator E. The rheostatR should be made as nearly as possible of the same resistance as the sounder S, in order to insure the best results in practice.

To illustrate the operation of the apparatus, let it be assumed that the relayM is open and that the relay M is closed. In this case the armature m will bear against the contact spring or tongue d, separating the latter from the front contact-point e. The armaturelever m of the other relay will rest against the stop b, thus permitting the contact spring 0! tongue d to rest against the front contactpoint e. The apparatus being in this position, the local circuit from the positive pole E will pass through the wire 1, contact spring or tongue d, armature-lever m, wire 3, and rheostat R to the point 4, thence through wire 5, contact spring or tongue d, front contact 6, wire 6, sounder S, and wires 7 and 8to the negative pole of the generator. Thus it will be understood that the current from the generator E will at all times find an unobstructed path through the circuit controlling device of each relay, passing through the sounder, as at S, when the armature-lever is on its front contact, and through a rheostat, as R, of an equal resistance, when the armature-lever is on its rear contact. One of these circuits is always closed at or before the interruption of the other, and hence the operation of any one instrument of the series in no manner interferes with that of any other. Any required number of relays and sounders may be placed in series in the branches of a single local circuit in this manner; but where thenumber of instruments to be provided for is,

large it is preferable to make use of a different organization involving-the same general principle, which may be termed a multiple series, and is represented in Fig. 2. In accordance with this plan any convenient number of local sounders S S S may be placed in parallel circuit or multiple arc with each other, so as to form a group. Another set of sounders, equal in number, S S S, may be placed in a second group, and still another set in a third group, and these three groups are then connected togetherin series, as shown in Fig. 2, the wires or conductors leading from the positive and negative poles of the generator being attached to the outer terminals, P N, of the series of groups. In case groups are formed in this manner of two or more sounders, with their accompanying relays or circuit-controlling devices placed in multiple are or parallel circuit, it is not necessary to employ a contact spring or tongue, in connection with the armature of each relay, for the purpose of closing the branch circuit through the rheostat before breaking the circuits through the sounder, and vice versa, inasmuch as the circuit is not liable to be interrupted in more than one of these branches at a time, and that only for an instant, so that. practically the connection is always complete, either through the front or back contact of one or more of the relays in each group. When a large number of instruments are arranged in this manner, the number of instruments placed in parallel circuit in each group, as well as the number of groups placed in series, should be governed by the ratio between the resistances of each individual sounder andthe internal resistance of the electric generator. As a general rule, the less the resistance of the generator and the lower its electro-motive force the greater the number of sounders which should be placed in each group and the less the number of groups in series. particular case may easily be determined by any person skilled in the art to which my invention appertains.

Iclaim as my invention 1. The combination, substantially as hereinbeforeset forth, of an armature-lever which is caused to vibrate to and fro between fixed stops by the attractive force of an electromagnet in a main-line circuit, a contact spring or tongue which bears against a fixed stop when said lever is in contact with its front stop, but is lifted therefrom by said lever when the latter is in contact with its back stop, and a local circuit having two branches, one containing a sounder or local receivinginstrument and closed by the contact of the tongue with the fixed stop, and the other containing an artificial resistance and closed by the contact of the armature-lever with the tongue, as set forth.

2. Two or more sounders or other telegraphic receiving-instruments placed in series in the same local circuit, and each provided with its own circuit-controller, in combination with electro-magnets included in different main-line circuits for independently actuating said circuit-controllers, substantially as set forth.

In testimony whereof I have hereunto sub,- scribed my name this 19th day of March, A. D. 1885.

FRANK L. POPE.

Witnesses:

CAROLINE E. DAVIDSON, CHARLES A. TERRY.

The most efficient arrangement in any 

